Geartrain noise in 4L60E second gear causing "knock" retard

[Fast355]

I am about to pull my hair out with this one. Have any of you seen a transmission cause false knock only in 2nd gear??? I can hear a whine in the transmission at about 4,000+ in second gear. At 4,400 I start seeing knock retard that quickly peaks 8°. I can slightly reduce the "knock by retarding the timing to rediculous values but not eliminate it. I made a run from a standing start to better than 90 mph and practically no knock in 1st or 3rd gear but massive amounts in 2nd that vanishes quickly after a WOT 2-3 shift, despite the engine being under more load, with more timing and less rpm.

Prior to the 0411 swap I ran a LT4 knock module and rarely ever saw knock retard even with 26-28° total advance.

Edit---This was meant for the OBD2 board...Darn phone.

[34blazer]

maybe talk to Dana at Probilt and find out what could cause the racket in 2nd gear?

[EagleMark]

Moved your thread for you. Wish I had an anwer but never dealt with this before.

Can you actually here some noise in second gear?

[Fast355]

Moved your thread for you. Wish I had an anwer but never dealt with this before.

Can you actually here some noise in second gear?

I appreciate you relocating this for me. Posting from my phone gets me sometimes.

Yes I can, sounds almost like a quiet gear drive the way it whines.

I messed around with it today and it responded very well to a Ramjet timing map. 30-31* total advance, 11.8:1 PE air/fuel ratio and 93 octane gasoline turned it into a rocket compared to how it was running. On another note....I am out of fuel at WOT now. Guess that TPI is going on sooner than later

The weirdest part of it all is sometimes it will retard the timing and other times it won't. I am seeing the same amount of retard at 18* timing as I am at 30-31*. I attached a few screen shots of 1st and 2nd gear runs and a WOT 1-2 shift.

[Fast355]

This is the stock spark map creating 8* of retard in 2nd gear! With this much knock on the stock tune, I do not feel this knock is actually knock, it has to be false knock.

[EagleMark]

The weirdest part of it all is sometimes it will retard the timing and other times it won't. Sure it's not Cat protection?

That log picture 3 looks like it may be trans torque reduction for shift?

[Fast355]

Sure it's not Cat protection?

That log picture 3 looks like it may be trans torque reduction for shift?


Cat Protection is Disabled along with EGR.

Torque management on 1-2 and 2-3 are both set more than stock at 40%. I had it at 50% reduction from stock, but with over 400 ft/lbs of torque in front of it the weak 4L60E was slipping between gears even with elevated line pressure, a transgo HD2 shift kit, and Corvette Servo. I put it back stock and I still didn't like the feel. I then put in more torque management and it really cleaned up the shift.

Look at the KR though in the 3rd picture it is 5.1*. Picture 1 was a 2nd gear pull running the Ramjet spark map and it peaked less than 1* at 4,800 rpm. Picture 2 has me less than 1* retard as well. The 4th picture is showing the stock timing map setting of 21* creating more than 8* knock retard! I am not even sure how that is possible at 11.8:1 air/fuel ratio.

[EagleMark]

Correct me if I'm wrong but torque management shows up as spark retard? Have no idea how you get more retard from less timing?

[Fast355]

Correct me if I'm wrong but torque management shows up as spark retard? Have no idea how you get more retard from less timing?

Torque management shows up as spark retard, but it does not show up as Knock retard. Notice the sharp dip on the upshift back to around TDC.

[Fast355]

So I remembered something that I ran across years back on a different swap. The 96-02 L30 305 Vortec and OBDII LT1, LT4 and L99 engines all use the same knock sensor and it is different than the 96-02 L31. At this point I am thinking of swapping to the L30 knock sensor or properly torquing it to 14 ft/lbs. I seem to remember an overtightened knock sensor becoming too sensitive.

[EagleMark]

Over tightening will do it and ruin the knock sensor.

Strange how OBDI knock sensors match engine displacement? Can you compare a 305 cal/bin/tun and a 350 cal/bin/tun? In EFI Live there's a ton of Knock sensor settings.

What's a HP Tuner file extension?

[Fast355]

I believe they are .BIN files. That being said I have a EFI Live .TUN file for both the 305 and 350 Express vans.

[RobertISaar]

HPTuners uses .HPT.

also, having a sensor too loose will also pick up false knock, or at least it does on 60V6 applications.

[sherlock9c1]

I don't suppose you ever get to 4400rpm in 4th... 2nd and 4th gear in the 4L60Es run the rear planetary gearset, and it's possible that this particular trans may have some needle bearings starting to wear. How many miles on it? Also, does it make any gear noise in reverse?

[Fast355]

I don't suppose you ever get to 4400rpm in 4th... 2nd and 4th gear in the 4L60Es run the rear planetary gearset, and it's possible that this particular trans may have some needle bearings starting to wear. How many miles on it? Also, does it make any gear noise in reverse?


Never have heard any noise in reverse. This trans is the original from 97 and has 80,005 miles as of this morning. Transmission has been JUNK since 38,000 miles. Just keeping it until I find the time to track down a 4L80E, rebuild it and swap it in.

Considering 3,100 rpm in 4th is 101 mph, 4,400 rpm is not going to happen with the current gearing and tire size.

[Fast355]

On a side note, I was driving home tonight with the windows down on the service road, next to an elevated highways retaining wall and ran it WOT from 0 through 75 mph. The whine I am hearing may even be accessory whine as its there in 1st gear too.

Ramjet timing tables woke this pig up. Also noticed a strong correlation between the 0411 MBT map and the Ramjet maps. On 93 octane a vortec 350 should have no issue at 30-31° of timing.

[sherlock9c1]

Do you have an underdrive pulley laying around that you could install to see if that changes the sound and the knock? Are the belt and tensioner in good shape (maybe it is slipping)?

[Fast355]

Do you have an underdrive pulley laying around that you could install to see if that changes the sound and the knock? Are the belt and tensioner in good shape (maybe it is slipping)?

Tensioner was replaced 23k miles ago with the engine and it has an underdrive pulley already installed. Belt was replaced with the underdrive pulley when the cam went in, about 1,000 miles ago. The clutch fan has already hit the spare parts shelf as well.

I wonder if it could be that Duracrap alternator that I had no choice but to install in middle of nowhere USA when the original started discharging at idle.

[Fast355]

So I found something interesting looking at the knock sensor calibration.....Specifically Burst Knock. I am going to do some datalogging with it limited to 1° and see what I see. I notice many guys just disable it on the LS engine and my TBI/TPI/CPI always had it disabled

[Fast355]

I am CERTAIN the knock sensor is lying to me though. At 3,500 rpm in 1st gear, heavy throttle PE @ 12:1 afr, commanding a mere 19° of advance, I was getting 7.8° of retard, that gradually tapered off as the rpm climbed, to less than 1° at 5,200 rpm.

[Fast355]

Now I am getting somewhere. Removed 2° additional CTS compensation at 205+ and ran with the burst knock at 0. Only saw a few brief points of 2° retard and that was mostly in OD when the TCC locks. Going to need that 3.73 G80 sooner than later. Now that I have the P0128 code turned off, I'll stick my 170°F thermostat back in. That will safely bring me up from 24-25° of timing to 28-29° by keeping the engine and IATs lower.

[pmkls1]

Speaking in terms of pure speculation I am going to say that your problem most likely isn't related to the noise you are hearing regardless of the source. This is based on your experiences with timing changes etc. It sounds to me like you are on the right track with tuning and lowering coolant temps etc. Just my 2 cents on the noise, if the trans does have a 2nd gear specific noise then it would probably be in the rear planet and/or captured bearing as well as sunshell flex. I understand your desire to upgrade to a 4L80E, but just remember that they are heavier, take more power to operate, and are relatively more expensive generally speaking. They also have their inherent flaws to deal with. If you can build a trans then I'd say build a solid 4L60E instead. You can throw upgrades that basically just increase pressures and clamping forces at the trans all day long. But, if you don't actually upgrade the internals and have stock frictions that have seen slippage and been abused, then nothing is going to improve the function of the trans and you might actually be worsening the problem.

[EagleMark]

I like burst knock, especially on high advanced spark tables. It's a anticipated knock for like cruising highway speed lite throttle and a quick accelerate it will keep you out of knock. Does not effect WOT. Great for heavy rigs. So when you get this issue fixed don't rule out leaving it off.

[Fast355]

Speaking in terms of pure speculation I am going to say that your problem most likely isn't related to the noise you are hearing regardless of the source. This is based on your experiences with timing changes etc. It sounds to me like you are on the right track with tuning and lowering coolant temps etc. Just my 2 cents on the noise, if the trans does have a 2nd gear specific noise then it would probably be in the rear planet and/or captured bearing as well as sunshell flex. I understand your desire to upgrade to a 4L80E, but just remember that they are heavier, take more power to operate, and are relatively more expensive generally speaking. They also have their inherent flaws to deal with. If you can build a trans then I'd say build a solid 4L60E instead. You can throw upgrades that basically just increase pressures and clamping forces at the trans all day long. But, if you don't actually upgrade the internals and have stock frictions that have seen slippage and been abused, then nothing is going to improve the function of the trans and you might actually be worsening the problem.

I have made up my mind on the 80E and have a core to build already. The 60E is a TRASH transmission, I have had one built professionally by a reputable performance shop (killed it in 15K) and had 3 others that I built with good components. You hit a point where you end up destroying cases on them or other hard parts with relatively little power. You just cannot make them hold up in a 6,000 lbs vehicle making 450+ TQ with a 2.6 STR converter. 80E has better gear spacing and the durability is well worth the slight power loss. The build I am looking at copying on my 350 made 490 ft/lbs of torque at the flywheel. With a 2.6 STR converter I will be looking at over 1200 ft/lbs torque spikes to the input shaft. The 60E does not stand a chance against that.

[Fast355]

I like burst knock, especially on high advanced spark tables. It's a anticipated knock for like cruising highway speed lite throttle and a quick accelerate it will keep you out of knock. Does not effect WOT. Great for heavy rigs. So when you get this issue fixed don't rule out leaving it off.

It also subtracts timing in 1st gear on a WOT jab and right after WOT downshifts. I am not a big fan of letting the PCM predicte something that might happen 1 time in 50 events. Properly tuned spark tables including AFR, CTS and IAT along with properly timed PE will keep you out of knock ALL the time.

I ALWAYS disabled Burst knock on my TBI engines. Never was a fan of it and never had issues without it. My 4.7 and Hemi engines had the same thing on them. I dropped nearly 2 tenths in my 60' in my Hemi Ram disabling, aka zero'ing out the TPS activated timing retard. Basically dodges version of burst knock. With the right timing and power enrichment delay bypassed never had an issue with knock either. Nothing like being heat soaked in hot weather, with a loaded trailer, high IATs and high CTS readings, A/C kicked on and hardly being able to move forward out of a traffic light due to all the unecessary timing retard.

[greggbruceauto]

The 60E is a TRASH transmissionI've built 700's for 502, supercharged 383's (600 rwhp) and nitrous cars... have had a couple issues, but they're still running....
the planets are actually bigger than 4L80E, but the hard parts actuating things are different, and the 80E does have an extra planet in front for overdrive, it for sure is heavier duty. Will be good to know how stuff works out...

[Fast355]

I've built 700's for 502, supercharged 383's (600 rwhp) and nitrous cars... have had a couple issues, but they're still running....
the planets are actually bigger than 4L80E, but the hard parts actuating things are different, and the 80E does have an extra planet in front for overdrive, it for sure is heavier duty. Will be good to know how stuff works out...

I tore the case lugs off the side of the case in one. Broke the "beast" sun shell in another and broke an aftermarket input drum in another. Each time it looked like a grenade had gone off inside. The weakest point gave out and when it failed, took the whole unit out. I had one that cracked in the bellhousing area as well on a stock 2.8 S-truck.

I picked up the ATSG manual on the 4L80E and plan to build it myself. I will let you know how it works out. The beefier OD is one of the main things I am after, since I plan to swap either 4.10 or 4.30 gears into it and will be towing in OD.

[greggbruceauto]

I tore the case lugs off the side of the case in one. Broke the "beast" sun shell in another and broke an aftermarket input drum in another. Each time it looked like a grenade had gone off inside. The weakest point gave out and when it failed, took the whole unit out. I had one that cracked in the bellhousing area as well on a stock 2.8 S-truck.

I picked up the ATSG manual on the 4L80E and plan to build it myself. I will let you know how it works out. The beefier OD is one of the main things I am after, since I plan to swap either 4.10 or 4.30 gears into it and will be towing in OD.
very cool -- not too difficult to do, the 60's and 80's are easier than the other brands (engineered WAAAAYYY better)...and practice makes you better....
I figured out on a couple of them the reverse boost valve "upgrade" made too much pressure and broke things.
also the pressure regulator spring "upgrade" in some of the shift kits do the same thing. I lowered the pressure (stock spring) a little and hit the magic button, things stayed together better.....

[RobertISaar]

I had one that cracked in the bellhousing area as well on a stock 2.8 S-truck.

you know something is awesomely engineered when a ~125HP/~155TQ engine in a ~2700 lb vehicle can kill it. :laugh:

i've had bad experiences with 700R4s in the past.... not so sure i would want to deal with another or something that was derived from it.

[Fast355]

Gotta love it...Knock retard entirely in 2nd gear but absolutely none at the 2-3 shift. I ran it 107 mph in 3rd gear at 4,500 rpm with the converter force locking at 85 mph and had less than 2* of knock retard and was pushing 200+*F coolant temps. That was as fast as the brick would roll into the wind up a slight grade.

[EagleMark]

And you can't hear a noise of feel a vibration in second gear?

[Fast355]

And you can't hear a noise of feel a vibration in second gear?


It does have a slight whine/vibration that is most noticeable in 2nd gear.

[Fast355]

As a few may know, I nuked first gear in the 60E on wednesday. Not having built my 4L80E core yet, I picked up a 97K mile used 4L80E from a 2002 Express G2500 with a 4.3 for $625.00 with a 6 month warranty.

http://i243.photobucket.com/albums/ff172/Fast355_album/20130809_102516_zps4bd895cd.jpg

http://i243.photobucket.com/albums/ff172/Fast355_album/20130809_102509_zps248b0831.jpg

[pmkls1]

Dang, $625 seems high even with the warranty, but they are a little tough to find.

After thinking about my post way back about just building a good 4L60E I realized that I hadn't taken into account what you drive and what you use it for. Having something that big and heavy and towing with it does make swapping in a 4L80E the better choice. That brings me to a good point, though. Most people don't understand the way that a transmission's rating is calculated. It isn't just horsepower that is taken into account. Actually, horsepower isn't taken into account, torque is. But torque is just part of the equation, gross vehicle weight is the other part. Lets say you have a 500 horsepower engine for example. If it's in a 2500lb car it still isn't going to place the same strain on the drivetrain as if that same engine were in a 5000lb van. Then add the towing weight on top of that and you have more strain with the same engine. That's how GM rates their transmissions and that is why you can have a 180hp 4.3 in a van and they put a 4L80E behind it, but you can have a 400hp 6.0 in a vette with a 4L65E behind it.

My point is, the 4L60 variants are more than capable and adequate for performance use and are often underestimated. But, it your particular case Fast355, you were right that a 4L80E is much better suited for your application. Good luck and I hope that the swap goes smoothly.

[Fast355]

Glad we agree! Not to mention the 4L80E has much better gear spacing than the 4L60e for accelerating something heavy. I am thinking of dropping to 4.30 gears with my 29" tall tires. I guess I should mention my accelerator gets used as an on/off switch quite often so I have a feeling I will be much happier with the 80E. Having a passing gear at 70 mph might be fun.

They wanted $1000 on ebay for similar units and $600-$800 on craigslist. Found a whole running 5.7 with accessories and trans from an 02 van with 80k for $850 but the seller would not pallet or ship from Mesa, AZ.

[RobertISaar]

yeah, 4L60 gear ratios are pretty much equal to the 4T60 gear ratios in term of crappy. the 1-2 shift always kills me, WAY too much RPM drop.

[delcowizzid]

the biggest trouble i have with 4l60 and 60e is shifting to 3rd under high boost they just seem to refuse to change under heavy torque load

[Fast355]

the biggest trouble i have with 4l60 and 60e is shifting to 3rd under high boost they just seem to refuse to change under heavy torque load

I cannot keep a 60e in one piece. They either don't have enough line pressure and smoke clutches or hard parts break. This is about the 7th one I have killed.

[pmkls1]

the biggest trouble i have with 4l60 and 60e is shifting to 3rd under high boost they just seem to refuse to change under heavy torque load

With the 700-R4/4L60 I have experienced issues with WOT 2-3 shifts (or a lack of them rather) because the throttle valve in the valve body will hang due to weak spring pressure and wear. I believe there are also a couple of other hydraulic issues that will cause this, but with a well built unit with the proper valve body components I have seen them work just fine behind big hp motors. You also have the governor and an encapsulated ball that can hang up and cause issues with shifting. I haven't really messed with many 700's behind highly modified engines and none behind a boosted engine, but power is power. I also haven't seen this problem in a 4L60E and thought that it was confined to the mechanically operated variants. There have, however, been many changes made to the 4L60E and it's later variants and most of those changes were in the valve body area. I've worked on far more later versions than earlier versions, so perhaps this is an issue that was more prevalent in the earlier versions.


I cannot keep a 60e in one piece. They either don't have enough line pressure and smoke clutches or hard parts break. This is about the 7th one I have killed.

This is what I was talking about is that you are exceeding the torque capacity of many of the components of the trans and that is why you can find a 4L80E behind a dinky 4.3 in the express vans. You could technically build a 4L60E that could handle the abuse, but it would easily cost $2k to do so. That is why in your case I agree that upgrading to a 4L80E is the better choice. You have a 5000lb+ van that you also tow with and have an engine that produces excellent torque so the increase in weight and power required to operate the 4L80E are insignificant. BUT, in many cases people are throwing a 4L80E into a CAR that takes more power to operate and adds weight to the vehicle simply because they lack the knowledge to properly build and/or cannot obtain a properly built 4L60 variant. In cases where you have a street rod or a street/strip car, you wouldn't want to make it heavier or purposely add more parasitic drag on the engine which is what installing the 4L80E will do. This is essentially the same as the age-old th350 vs. th400 argument in a couple different ways. First, the 4L60/E and the 4L80E are directly derived from the th350 and th400 respectively and share some of the weaknesses and strengths as well as some parts and special tools. For example, the center support lugs around the snap ring in the 4L60 variants are prone to breakage and are well known problem areas. This is in fact a problem that is not only carried over from the th350, but the same exact fix and even part number that was engineered for the th350, a bolt in center support, works in the 4L60 variants. Neither the 4L80E nor the th400 had this issue due to the design of this area. The 4L80E actually carries over the same exact gear ratios just adding the overdrive gear in 4th, but unfortunately the 4L60 got different ratios to help the pathetic 150hp V8's of the era get heavier vehicles going during the time-period it was originally developed. Then you get back to the issue of the th400 being heavier and taking more power to operate than the th350, which carries over to the 4L60/E vs. 4L80E argument. Now, because of the simplicity of the th350 and the amount of parts engineered for serious hp applications and more people will argue on behalf of the th350 than those that would for the 4L60/E. But, the 4L60 variants do have a place in the market and do have some advantages over the 4L80E, it just depends on the application, skills, and budget of the owner.

On a side note I did have some other comments to make.
While searching for good aftermarket parts to rebuild the mother-in-law's 4T65E, I found that geartrain noise in them actually will cause false KR and it is common for people to install a sheet of dynomat on the side of the trans that runs alongside the engine and around the knock sensor on that side of the engine. Now, obviously with these transmissions, noise is going to reach the knock sensors a lot easier because the knock sensor is within a couple of inches of the geartrain in a nearly enclosed environment that doesn't give the noise anywhere to go. But, it does demonstrate how noise from the trans can cause KR issues. I had a similar issue with my Nissan 240sx where the mainshaft bearings in the trans (5 speed manual) were problematic and would develop pitting in the races and roar. This roar was audible in neutral with the clutch out it was so loud and it would transmit back through to the block and trigger KR while driving.

Also, if you really want a transmission that's bulletproof and has good gear ratios then the 6L80E/90E is where it's at. That is, is you've got the big bucks to fork over for one. They are truly badass transmisssions and people are putting them behind 1000+hp engines with practically no internal modifications. I've worked on a basically stock LS2 powered C6 Vette that had nothing more than a cold air intake and a performance tune done at a local performance shop and it broke the rear wheels loose on the 2-3 shift at somewhere around 80mph. Talk about leaving skidmarks..........in my shorts ! The power was nothing new as a bone stock LS2 is rated at 400hp and this one was in LS3 territory at around 430hp which is nice, but not super special these days and I was used to driving Vettes and souped up Camaros that regularly put out over 500hp. But, to have a basically stock automatic trans car cock sideways when upshifting at 80mph is definitely an adrenaline rush, especially if you're not expecting it. Back to the transmissions though, other than requiring specific electronics to function and the cost of acquiring one, they're an excellent candidate for high torque-load applications. Another feature that I like about them that is actually in the controller programming is using tow/haul mode in the trucks. Unlike the 4L60E variants that had tow/haul mode, the trucks equipped with the 6L80E truly benefit from using tow/haul mode when pulling something heavy. The upshifts are easily noticeable as being at a higher RPM and firmer, but it's when you step on the brakes that you'll be surprised. They will downshift quite aggressively when braking to provide a very generous amount of engine braking to aid in stopping and if you're not prepared it'll definitely get your attention. Like I said, this feature is mainly in the controller programming. But, since they have 6 gears, they can continue downshifting and provide much more consistent engine braking than a 4 speed. With a 4 speed, the gear ratios are spaced farther apart and you have to slow down so much before being able to downshift into the next gear. So, you'll get lower in the RPM range and lose some engine braking before downshifting to the next gear and then you get another big surge of engine braking. They also aren't particularly heavy for their size and torque capacity and have extremely little issues. As a matter of fact, from the time that I began working around them in 2007 until I left Chevrolet last summer, I have never seen a mechanical failure in one personally and have only had to replace faulty controller/solenoid packs on the early models that had some issues.

Just my 2 cents.

[RobertISaar]

seems like more than 2 cents there. :laugh:

i think the idea behind using a 4L80 over a 60 is just because you can buy one, drop it in, setup the calibration and not have to mess with anything else and it will survive behind most any street-driven engine.

i'm also quite excited about the 6L and 6T transmissions these days.... they're not overly complicated to control if you remove the TCM(or somehow are able to interact with it), which is great news for me and my 1227730 based transmission controller.

[EagleMark]

seems like more than 2 cents there. :laugh:

Yeah at least a buck and a half? :laugh:

4l60E is fine till you put strain on it like adding HP. 4l80E in stock form will handle it.

[34blazer]

Just my 2 cents.

After all that I think I may be worthwhile to charge instead offering. LMAO

[EagleMark]

I'm wondering if there are differences in 4L80E trans from a 4.3L compared to 5.7L or 7.4L? Or are they all internally the same?

[RobertISaar]

likely some differences. would need to see if the transmission tags are the same. if not, something changed, even if it is something tiny.

[pmkls1]

Lol, I guess that was a lot more than 2 cents.

Yes, the easiest and probably cheapest solution for heavy duty applications is swapping out the 4L60E for a 4L80E, and that is why it is popular. And, the gear spacing is much better on the 4L80E for sure. For somebody that is building a high-dollar 4L60 variant, there is a company that makes a custom front planetary set that changes the 1st and 2nd gear ratios to much closer spacing. They are fairly expensive and are only going to be found in more exotic builds, but they do solve the problem and are even stronger than the later oem 5-pinion planetary sets.

Regarding controlling the 6L and 6T variants, in all of the 6L's and 6T's along with the 2ML70 (2 mode hybrid truck trans) the TCM is part of the solenoid pack assembly and is internal to the transmission (many actually share common part numbers). The issue with the modules isn't wiring them up per se, but the type of communication protocol they use. These modules use GM high speed LAN communications which is a twisted pair with 2 terminating resistors at either end of the circuit. Usually, one resistor is external and the other is inside of one of the modules. IIRC the resistors were 120K ohms each. With GM LAN systems, there is a high speed and low speed network with the BCM being the gateway module for communications, the power-moding module for all other modules, and also the only module being on both networks. All critical modules like the PCM, TCM, EBCM, SDM, etc... use the high speed LAN. Whereas, non critical modules like door modules, seat modules, radios, HVAC, etc..... use low speed LAN. Technically, it doesn't matter how many and which modules are on the high speed LAN network as long as the terminating resistors are there as well as the BCM since it controls the power mode of all other modules and it is how the scan tool communicates with the network. So, unless someone has engineered some sort of interface module for the TCM to communicate with an older style ECM and the scan tool, sticking one of these puppies in an older vehicle would be quite complex. But who knows, there may already be solutions out there. I just haven't had any experience with someone transplanting one of these transmissions.

As far as internal differences in something like a 4L80E with varying engine combos, I don't know of any. But, if there are any differences they would mainly be in the valvetrain inside the valve body and maybe accumulator springs. The clutch stacks and hard parts are all the same. The 4L60 variants had minor valvetrain differences based on application and used different accumulator springs and 2nd gear servos. There were also several different 3-4 clutch pack setups over the years as well, but this was more of a time progression than application specific change. And, of course, the torque converter is application specific on all of them. If you want a "po-boy" high stall converter, go with one that was used with a smaller engine and you'll get slightly higher stall speed.

[RobertISaar]

2.2 S10 would be the where i would look for a high stall.

oh, and my planned method is a bit more.... involved, due to the unknowns of the TCM. involves gutting the TCM and running more wiring external to the case.

[pmkls1]

2.2 S10 would be the where i would look for a high stall.

oh, and my planned method is a bit more.... involved, due to the unknowns of the TCM. involves gutting the TCM and running more wiring external to the case.

Now that is another possible solution to the problem. I can tell you that the TCM is very complex and far more sophisticated than any previous controllers. The calibration files have to be huge and the processing power has to be pretty impressive because there are so many variables in the calibrations. The adaptive shifting is also pretty complex and these transmissions won't even shift right until the controller has gone through a specific learn sequence. I can't remember for sure, but I think the solenoid packs have 5 solenoids. The configuration is odd, though, and how it uses the solenoids for control is a little different. I'm not trying to scare you off of them, but developing solutions for the 6 speed automatics is definitely not for the faint of heart. Even the torque sequence for securing the TCM/solenoid pack to the valve body is very critical to avoid putting the solenoids in a bind. But, there aren't any issues with the TCM/solenoid pack or the rest of the trans as far as durability is concerned. Transmissions with properly installed and programmed TCM/solenoid packs typically work very well and last a long time without experiencing any issues at all even when abused.

The only 6 speeds that have had any common internal issues are the 6T70/75E models and most of those issues have been resolved with the later models experiencing little or no issues at all. I believe the original problem was exacerbated by technicians that were repairing failed units not properly cleaning all of the debris out of the cases and coolers which would cause the repaired units to fail rather quickly. The actual source of the issue, which I believe was a defective wave plate for one of the clutch packs, was addressed a few years ago. But, the recurring issues with previously failed units led to an incorrect belief by some that the transmission was junk.

Anywho, that's my 2 bucks worth lol

[RobertISaar]

some info i've collected on the 6 speeds over the past couple of months:

6L45/50: ???
6L80/90: 2 shift solenoids, 1 VSS, 1 TCC PWM, 1 ISS. 5 PCS, 1 temp sensor (integral TCM)
6T30/40/45: ???
6T70/75: 2 shift solenoids, 1 VSS, 1 TCC PWM, 1 ISS, 5 PCS, 1 temp sensor (integral TCM)

6L80 and 6T70 have identical solenoid setups

6L50
4.06, 2.37, 1.55, 1.16, .85, .67, 3.2
6L80
4.027, 2.364, 1.532, 1.152, .852, .667, 3.064
6T40
4.584, 2.964, 1.912, 1.446, 1, .746, 2.94
6T70
4.484 2.872, 1.842, 1.414, 1, .742, 2.88

i've got a really neat set of PDFs explaining how the 6T70(and related) work, they're certainly complex, but nothing i can't handle.

[pmkls1]

some info i've collected on the 6 speeds over the past couple of months:

6L45/50: ???
6L80/90: 2 shift solenoids, 1 VSS, 1 TCC PWM, 1 ISS. 5 PCS, 1 temp sensor (integral TCM)
6T30/40/45: ???
6T70/75: 2 shift solenoids, 1 VSS, 1 TCC PWM, 1 ISS, 5 PCS, 1 temp sensor (integral TCM)

Would the "5 PCS" mean pressure control solenoids ? The 2 shift solenoids sounds like what I remember and I think I remember the TCC solenoid. It was the multiple pressure control solenoids that always threw me, but I didn't remember how many.


6L80 and 6T70 have identical solenoid setups

They all have the same basic solenoid setup actually. The actual controller assemblies are physically different between the FWD and RWD transmissions, but just about all of the RWD transmissions use the same part # for the controller/solenoid assembly. In the FWD models the 6T40 variants (6T40/45) are based off of the 6T70 series ( 6T70/75) so the controllers can possibly be the same part #. The 6T30 is based off of the same design too, but is physically smaller yet. Although, it likely has the same controllers as the others. In the RWD line even the 2ML70 that I mentioned earlier uses the same part number as the other RWD setups. At the last Chevy dealer, I was one of only two certified 2-mode hybrid techs out of the 17 technicians there so I would do minor trans repairs on them often just to keep the 1 1/2 trans techs out of the weeds. The first time that I had to replace the controller/solenoid assembly in a 2ML70 was fun because the part # was restricted. That meant a call to technical assistance to basically explain that I had gone through the proper diagnostic procedures and exactly what was wrong so they could document it. Then, because it was a hybrid, I had to wait for a call from an engineer that was involved directly in the development of those transmissions and talk to him personally before they would send me one. Luckily, the engineer wasn't a pious prick like many out there and was actually pretty cool. He told me that when the part was sent back that he would personally test it and gut it to pinpoint the problem so it made me a little nervous about my diagnosis. I still actually had to go so far as to completely disassemble the valve body and physically check every valve in it as well before a new module was sent out. Which, they are very simple compared to any other valve bodies as the complexity lies in the controller. Back to the RWD models, the 6L45/50 are basically just physically smaller versions of the 6L80/90 with the configuration being nearly identical. The earlier 5L40/50 were similar, but still had many differences.


i've got a really neat set of PDFs explaining how the 6T70(and related) work, they're certainly complex, but nothing i can't handle.

The mechanical operation is a little complicated compared to some of the older transmissions, but the real complexity lies within the code in the controller. I'm sure that a lot of the programming is unnecessary and is for emissions and/or driveability and could be completely eliminated. Things like the constant slipping of the TCC probably take a more complex algorithm than just controlling it in an on/off manner. A lot of the shifting algorithms could probably be simplified too since they are highly influenced by emissions and driveability concerns. In other words, someone that knows how the transmission is controlled by the solenoids could make one work (and probably work great) with a much simpler controller and code. I think that it would be nice to be able to just utilize the existing controller and pair it with a later model ECM, but I actually have problems with using a late model ECM. My biggest gripe with late model ECMs would be the need to use drive-by-wire, which I hate with a passion. My other gripe would just be the cost of OBDII tuning equipment. But, if I had the money for a late model 6 speed auto then I would probably be able to afford the tuning equipment :mad1: . Getting one of the late model TCMs to interface with an older ECM would be pretty neat too, but I don't see that being much if any less expensive than just going with a late model ECM setup which would have added benefits like coil-on-plug ignition etc....

[EagleMark]

Anywho, that's my 2 bucks worth lol Dam! I wonder what we would get for like $10? :thumbsup:

[pmkls1]

Dam! I wonder what we would get for like $10? :thumbsup:

Ummmm, you could get a plethora of random information that would take days to read and be of little use. LOL :popcorn:

[Hog]

2.2 S10 would be the where i would look for a high stall.

oh, and my planned method is a bit more.... involved, due to the unknowns of the TCM. involves gutting the TCM and running more wiring external to the case.
For a 4l60e behind a V8 look for a 1995+ 4.3 V6 TC, it will have the code DBLF on it. It gives about 2800rpm of stall rpm behind my L31 vortec 350.
The I-4 4l60e TC's are different and will not work.

peace
Hog

[BJackson]

The 4L60E has a common problem like this a lot…I would check out the blog at http://www.twincharlotte.com they list a lot of issues with the 4L60E transmission and common problems, symptoms and repair options.

[Fast355]

The 4L60E has a common problem like this a lot…I would check out the blog at http://www.twincharlotte.com they list a lot of issues with the 4L60E transmission and common problems, symptoms and repair options.

Except I have been driving around with an 80E swap for two months after grenading the 60E.

[brian617]

I messed around with it today and it responded very well to a Ramjet timing map. 30-31* total advance, 11.8:1 PE air/fuel ratio and 93 octane gasoline turned it into a rocket compared to how it was running. On another note....I am out of fuel at WOT now. Guess that TPI is going on sooner than later

Have a copy of that Ram Jet spark table I could eyeball? I googled around and found nothing.

[Fast355]

Have a copy of that Ram Jet spark table I could eyeball? I googled around and found nothing.

It is on Thirdgen.org, the copy I made from that info was converted to work with the LS style timing map. I also have a Hypertech spark map for a L31 with 5 speed. They only really made WOT changes due to emissions compliance though.